3-D printing helps small endangered turtle at Zoo Knoxville

10/27/2017

Call this one Phantom of the Turtles. Or the Case of the Masked Reptile.

But this story’s no Halloween tale. It’s all about an endangered species, three-dimensional printing and veterinary ingenuity. Meet Patches, a small Zoo Knoxville turtle sporting a teeny Halloween- style resin mask, courtesy of the 3-D technology at the University of Tennessee College of Veterinary Medicine. There’s even a bit of bright blue tinge in the form of a tiny titanium screw that secures the mask to the turtle.

The female black-breasted leaf turtle, about 5 1 ⁄ 2 inches long and estimated at about 30 years old, is a member of an endangered species native to northern Vietnam and southeastern China. She’s been at the park 10 years to breed and help save her species as part of the Association of Zoos and Aquariums’ Species Survival Plan.

Last August zookeepers discovered Patches had been hurt. They saw a puncture hole in her right nostril. The hole got infected and grew to cover part of her face.

Nobody is exactly certain how the turtle was hurt. But the park’s only adult male black-breasted leaf turtle could have injured her during an attempt at reptile romance.

“Male turtles are very rambunctious when they are trying to woo a female,” said Michael Ogle, the zoo’s herpetology curator.

After a year of treatment and at least one micro CT scan, zookeepers and UT veterinarians consulted on the turtle’s facial future. Dr. Andrew Cushing and Dr. Kyle Snowdon suggested creating a tiny, lightweight 3-D-printed mask made of resin.

The mask would cover the puncture, making it easy for Patches to eat as well as keep out moss, dirt and possible infection.

“It wasn’t going to do her any harm to try,” Ogle said.

Three-dimensional printing is among techniques used in veterinary medicine. At UT, it’s often used to create models of animal bones so that surgeons and students can practice difficult surgical techniques. Creating Patches’ mask was the first such use of 3-D printing at the Tennessee veterinary college. But at other institutions, veterinarians have created 3-D legs and beaks for birds.

Snowdon used specialized computer software to print a three-dimensional model of Patches’ skull. Then he printed various 3-D resin masks that could fasten on her head.

“We had to look at different ways to get to it. It had to be the right size so the turtle could get its head in its shell. It could not cover the nostrils,” Snowdon said.

As a “learning experience,” Snowdon also created a couple of impractical masks. One looked like a shark fin; the other had two small rhino horns.

This June, an initial mask was secured on Patches’ head with adhesive. While she tolerated the cover, it didn’t stay on long. Last month, a second, more lasting mask was printed and placed on the reptile.

Patches’ new mask — made of clear, strong resin — isn’t just headgear. A micro CT scan showed that the injury basically destroyed her mouth’s hard palate. So doctors wanted to help correct that problem, too.

The second mask was placed atop the turtle’s skull and secured with the screw placed through the existing puncture hole. The screw goes in the top of Patches’ mouth, where it’s secured with a dab of composite resin.

That resin, similar to that used to fill human dental cavities, created a new roof in Patches’ mouth.